Intraocular gas injector

ABSTRACT

A gas mixture apparatus includes a measurement control system, an activation system, a pressurized chamber with one or more gases, and a mixing chamber. The apparatus can also include additional pressure regulation control systems. The gas mixture apparatus can be used to introduce and automatically perform the steps to achieve a desired concentration of the one or more gases contained in the pressurized chamber. The gas mixture apparatus can include the pressurized chamber within the apparatus itself such that no external devices are necessary for introducing the one or more gases into the mixing chamber.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 61/658,765 filed Jun. 12, 2012, entitled INTRAOCULAR GAS INJECTORand U.S. Provisional Application No. 61/799,840 filed Mar. 15, 2013,entitled INTRAOCULAR GAS INJECTOR, the entire contents of both of whichare hereby expressly incorporated by reference.

TECHNICAL FIELD

The inventions disclosed herein generally relate to devices and methodsfor injecting gases into an eye of an animal.

BACKGROUND OF THE INVENTIONS

Surgical procedures can require gases or other fluids to be injectedinto a target area for treatment of certain injuries, disorders anddiseases. In the treatment of eye conditions such as macular holes,retinal tears and detachments, part of the surgical procedure caninclude the injection of gases or other fluids into the eye.

For example, retinal detachment is an eye disorder involving theseparation of the retina from the Retinal Pigment Epithelium (RPE), thetissue that holds the retina in place. Retinal detachment can occur dueto a retinal tear, traction on the retina, or inflammation which allowsfluid to build up in the subretinal space thereby causing the retina tobegin to separate from supporting RPE tissue. This disorder can alsooccur due to Posterior Vitreous Detachment (PVD), Proliferative DiabeticRetinopathy (PDR), injury, or neovascularization of the fibrous orvascular tissue causing the retina to be detached from the RPE. Such acondition, if not treated immediately, could lead to partial vision lossand potentially even blindness.

Treatment approaches for uncomplicated retinal detachments may includenon-surgical techniques such as pneumatic retinopexy, laserphotocoagulation, or cryopexy. More complicated retinal detachmentsrequire surgical intervention. Due to the risk of infection, which canpotentially cause blindness, such surgeries are performed under sterileconditions in order to significantly reduce the potential for infection.Surgical methods include vitrectomy, which is the removal of thevitreous humor; dissection and removal of membranes, in the case oftraction retinal detachments; and photocoagulation or cryopexy, in thecase of additional retinal tears. Following such a surgical procedure,an intraocular gas tamponade may be used to hold the retina tissue incontact with the RPE which enables the retina to remain attached duringthe healing process after the surgical procedure.

Since intraocular pressure must be maintained relatively constant duringthe healing process, the gas chosen is typically one that expands atconstant pressure (isobaric process). As such, the intraocular gastamponade can be a gas bubble of air mixed with an expansile gas such assulfur hexafluoride (SF₆), hexafluroethane (C₂F₆), or octafluoropropane(C₃F₈). The intraocular gas tamponade dissolves over time depending onthe gas and concentrations used. For example, sulfur hexafluoridedissolves within 1-2 weeks when mixed with air at a concentration ofapproximately 20 percent, hexafluoroethane dissolves in approximately4-5 weeks when mixed with air at a concentration of approximately 16percent, and octafluoropropane dissolves in approximately 6-8 weeks whenmixed with air at a concentration of approximately 12%. Changing theconcentrations of these gases affects the duration.

Current practice involves use of gases contained in separate, multi-dosepressurized containers which are then transferred into a syringe formixing with air and injection into the patient's eye. Therefore, duringa surgical procedure, multiple non-sterile and sterile steps arerequired in order to fill the syringe with a desired concentration ofgas and air. These non-sterile and sterile steps are typically performedby the non-sterile operating room circulating nurse and the sterilescrub technician supporting the surgeon in the sterile field. During afirst non-sterile step, the circulating nurse prepares the non-sterilere-usable gas container by setting a pressure regulator connected to thegas container at the proper pressure. During a second step, the scrubtech prepares a sterile syringe by connecting a stopcock, filter, andtubing, in series, onto the syringe. During a third step, the tubing isconnected to the gas container. The scrub tech carefully passes the freeend of the sterile tubing through the invisible sterile barrier to theawaiting non-sterile circulating nurse. The non-sterile circulatingnurse receives the tubing and carefully ensures that he/she does notcontaminate the scrub tech nor any other of the sterile surfaces; andconnects the tubing to the regulator on the gas container. During afourth step, the syringe is then filled with gas from the container. Thescrub tech and circulating nurse coordinate the opening of thepressurized container valve to release gas through the connected tubing,filter, stopcock, and into the syringe. The pressure of the released gasis sufficient to push the syringe plunger along the length of thesyringe barrel and thus fill the syringe with gas. The scrub techensures that the gas does not push the plunger out of the open end ofthe syringe barrel and signals to the circulating nurse to close the gascontainer valve when the syringe approaches a fully filled condition.During a fifth step, the syringe is then purged of all air and gas inorder to ensure that a substantial majority of air which may have beenpresent within the syringe, stopcock, filter, and tubing, prior tofilling with gas has been purged. The scrub tech turns the stopcock, toprovide a means for the air and gas in the syringe to be released to theatmosphere, presses on the syringe plunger, and empties the syringe ofall of its contents. The scrub tech then turns the stopcock in theopposite direction, returning the connection pathway to the tubing andthe gas container. Steps four and five are repeated several times tofurther reduce the amount of air that was initially in the syringe,stopcock, filter, and tubing; flushing the majority of the air from thesyringe, stopcock, filter, and tubing and purging the system of air.During a sixth step, the syringe is then refilled with gas from thecontainer. The scrub tech detaches the tubing from the filter andsignals the circulating nurse to carefully take the tubing, removing itfrom the sterile field. During a seventh step, the scrub tech does notexpel the full contents of the syringe, stopping the plunger such thatonly a measured volume of gas remains in the syringe. For example, thegas may be expelled such that only 12 mL remains within the syringe.During an eighth step, the scrub tech replaces the used filter with anew sterile filter and draws filtered room air into the syringe untilthe total air/gas mixture in the syringe is at a proper volume for thedesired gas concentration.

For example, atmospheric air may be drawn into the syringe such that thetotal volume of air and gas is 60 mL therefore achieving a concentrationof 20 percent. Since the pressurized containers are non-sterile, and thesyringe and surgical area are sterile, completing the above-mentionedsteps must be performed by at least one party in the non-sterile field(typically the circulating nurse), a second party in the sterile field(typically the scrub tech), and requires the coordination andcommunication between the two parties.

The procedure requires a complex set of steps which may increase thepotential for errors occurring. An error in one of these steps canresult in an improper concentration of gas being used which may resultin having either an elevated pressure or reduced retinal tamponadeduration thereby potentially causing ischemia or failure of thereattachment surgery, both of which potentially causing blindness.Additionally, the current practice results in a significant amount ofwasted gas which is both expensive and harmful to the environment. Thushandling of such gases, especially in pressurized containers containingmore than one dose, may present potential danger to the operator ifmishandled. As such, some countries may even prohibit storage of thesepressurized containers in the operating room.

While there have been some approaches to improve the current procedure,such as U.S. Pat. No. 6,866,142 to Lamborne et al., single-dosecontainers capable of being placed in the sterile field, and the Alcon®Constellation® system which allows filling and purging of gas, theseapproaches have been insufficient to address all the potential issues.As such, there remains a need in the industry for an improved gas mixingapparatus.

SUMMARY OF THE INVENTION

An aspect of at least one of the inventions disclosed herein includesthe realization that an intraocular gas injector design can allow asurgeon or a nurse to prepare a gas mixture with a selectedconcentration level using a simplified procedure. For example, in someknown intraocular gas injector devices and procedures, such asconventional syringes, multiple parties can be required to fill thesyringe to achieve a desired concentration with one person repeatedlyfilling and discharging the syringe and another person controlling theflow of a gas contained in an external tank. Additionally, each personmust coordinate their actions and perform a multitude of complex steps.This increases the potential for errors in the filling process whichcould result in an improper concentration being achieved in the syringeprior to injection into a patient. Furthermore, this can increase thetime necessary to fill the syringe as the two parties must coordinatetheir activities and perform multiple steps. The potential for error canbe particularly dangerous in certain medical fields, such asophthalmology, where injection of an improper concentration can resultin blindness. Thus, an intraocular gas injector that can be operated bya single person can help reduce the likelihood of error.

Another aspect of at least one of the inventions disclosed hereinincludes the realization that an intraocular gas injector design canallow for multiple selectable concentration levels thereby allowing onedevice to be used for different applications and thus potentiallyfurther reducing manufacturing costs and waste. For example, someconventional devices can only allow for a preset concentration level tobe achieved within the device thereby necessitating the manufacturingand storage of multiple devices having different preset concentrationlevel. This increases both the costs of manufacturing and the cost to asurgeon who needs to purchase multiples of each device to accommodatefor different surgical needs. Under such circumstances, some devices canexpire thereby requiring the manufacturer or surgeon to dispose of suchdevices without ever having been used. As such, an intraocular gasinjector that allows for multiple concentration levels can serve as aone-size fits all for a surgeon thereby reducing waste.

Another aspect of at least one of the inventions disclosed hereinincludes the realization that an intraocular gas injector design canallow for automated operation during at least some phases of operationthereby reducing the potential for errors in achieving a properconcentration level. For example, in some known intraocular gas injectordevices and procedures, such as conventional syringes, a nurse or otheroperating room personnel must physically measure the amount of gascontained within a syringe during a first phase of operation. In asituation where a minute change in volume can result in a significantchange in concentration, a minor error in this physical measurement canresult in an improper concentration being achieved in the syringe afterall phases of operation have been completed. Therefore, an intraoculargas injector that automatically measures the volume in the first phaseand/or any other phase can reduce the likelihood of an improperconcentration being achieved in the injector.

Another aspect of at least one of the inventions disclosed hereinincludes the realization that an intraocular gas injector design can bemade with a canister within the injector, with the canister capable ofbeing filled separately prior to incorporation into the injector,thereby reducing the costs of manufacture. Thus, for example, anintraocular gas injector device can include a separate canister placedwithin the body of the injector.

Yet another aspect of at least one of the inventions disclosed hereinincludes the realization that an intraocular gas injector design canincorporate a storage member having an internal valve mechanism therebyreducing the costs of manufacture of the injector. For example, in somedesigns, the device can use multiple pressure regulation systems, suchas check valves, integrated on components of the device to regulatepressure within the device and to control the operation of the device.The integration of pressure regulation systems on components of thedevice can result in increased manufacturing costs for those components.Thus, the relocation of valves to the storage member can help reducemanufacturing costs of the device if the cost of manufacturing of aninternal valve mechanism within the storage member is lower than thecost of manufacturing a valve integrated on other components of thedevice.

An aspect of at least one of the inventions disclosed herein includesthe realization that an intraocular gas injector design can incorporatean interlock mechanism configured to control the movement of anactivation switch thereby reducing potential erroneous operation of theinjector. For example, in some designs, the device can include anactivation switch which can control the operation of the device such asthe opening and closing of a pressurized chamber within the device. Insome instances, the user can use the activator switch to reopen thepressurized chamber within the device when such opening can cause animproper concentration to be received. An interlock mechanism configuredto control the movement of an activation switch can help reduce thelikelihood of erroneous operation of the injector.

An aspect of at least one of the inventions disclosed herein includesthe realization that an intraocular gas injector design can allow forautomated operation during at least some phases of operation whenconnected to an external pressurized chamber thereby reducing thepotential for errors in achieving a proper concentration level. Forexample, in some known intraocular gas injector devices and procedures,such as conventional syringes, a nurse or other operating room personnelcan connect an external gas tank to the syringe and repeatedly fill anddischarge gas within the syringe to ensure that the syringe containsmainly gas from the tank. During these refill and discharge cycles,another party may need to open and close a valve on the external gastank. Thus, for example, an intraocular gas injector can allow theattachment of an external pressurized chamber and automatically reach aconfigured volume and discharge gas such that the injector containsmainly gas from the external pressurized chamber.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a first embodiment of a gas mixture apparatus.

FIG. 2A is a second embodiment of a gas mixture apparatus shown in aninitial phase of operation.

FIG. 2B is a second embodiment of a gas mixture apparatus shown in afirst phase of operation.

FIG. 2C is a second embodiment of a gas mixture apparatus shown in asecond phase of operation.

FIG. 2D is a second embodiment of a gas mixture apparatus shown in athird phase of operation.

FIG. 3 is an exploded view of the components of the second embodiment ofa gas mixture apparatus.

FIG. 4 is a perspective view of a measurement control system andactivation system of the second embodiment of a gas mixture apparatus.

FIG. 5A is a perspective view of a metering dial of the secondembodiment of a gas mixture apparatus.

FIG. 5B is a sectional view of a metering dial of the measurementcontrol system of FIG. 4.

FIG. 6 is a perspective view of a plunger body of the measurementcontrol system of FIG. 4.

FIG. 7 is a perspective view of the activation system of FIG. 4.

FIG. 8A is a sectional view of the measurement control system andactivation system of FIG. 4 in a first or “closed” position.

FIG. 8B is a sectional view of the measurement control system andactivation system of FIG. 4 in a second or “open” position.

FIG. 9 is a side view of an embodiment of an activation system,pressurized chamber, and first pressure regulation system of the secondembodiment of a gas mixture apparatus.

FIG. 10 is a sectional view of the activation system, pressurizedchamber, and first pressure regulation system of FIG. 9 in a firstposition.

FIG. 11 is a sectional view of the activation system, pressurizedchamber, and first pressure regulation system of FIG. 9 in a secondposition.

FIG. 12 is a sectional view of components including a mixing chamber andsecond pressure regulation system of a second embodiment of a gasmixture apparatus.

FIG. 13 is an enlarged sectional view of the mixing chamber and secondpressure regulation system of FIG. 12.

FIG. 14 is an enlarged sectional view of the mixing chamber and secondpressure regulation system of FIG. 12 with an additional attachment.

FIG. 15A is a perspective view of a metering dial of an embodiment of ameasurement control system.

FIG. 15B is a sectional view of a metering dial of an embodiment of ameasurement control system.

FIG. 16 is a perspective view of a plunger body of an embodiment of ameasurement control system.

FIG. 17 is a perspective view of components of an embodiment of anactivation system.

FIG. 18 is a sectional view of a measurement control system andactivation system in a first, “initial”, or “pre-activation” positionshowing operation of an interlock mechanism.

FIG. 19 is a sectional view of a measurement control system andactivation system in a second or “open” position showing operation of aninterlock mechanism.

FIG. 20 is a sectional view of a measurement control system andactivation system in a third or “closed” position showing operation ofan interlock mechanism.

FIG. 21 is a sectional view of a measurement control system andactivation system in a first, “initial”, or “pre-activation” positionshowing operation of the latch.

FIG. 22 is a sectional view of a measurement control system andactivation system in a second or “open” position showing operation ofthe latch.

FIG. 23 is a sectional view of a measurement control system andactivation system in a third or “closed” position showing operation ofthe latch.

FIG. 24 is an enlarged view of an embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system.

FIG. 25A is a sectional view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 24 in a first, “initial”, or “pre-activation” position.

FIG. 25B is an enlarged view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 25A.

FIG. 26A is a sectional view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 24 in a second or “open” position.

FIG. 26B is an enlarged view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 26A.

FIG. 27A is a sectional view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 24 in a third or “closed” position.

FIG. 27B is an enlarged view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 27A.

FIG. 28 is an enlarged view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 25A illustrating in more detail an embodiment of a storage member.

FIG. 29 is an enlarged view of the embodiment of an activation system,pressurized chamber, and a storage member pressure regulation system ofFIG. 26A illustrating in more detail an embodiment of a storage member.

FIG. 30 is a sectional view of an embodiment of a syringe body andsyringe pressure regulation system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the proceeding technical field, background,brief summary, or the following detailed description.

Certain terminology may be used in the following description for thepurpose of reference only, and thus are not intended to be limiting. Forexample, terms such as “upper”, “lower”, “above”, and “below” refer todirections in the drawings to which reference is made. Terms such as“proximal”, “distal”, “front”, “back”, “rear”, and “side” describe theorientation and/or location of portions of the component within aconsistent but arbitrary frame of reference which is made clear byreference to the text and the associated drawings describing thecomponent under discussion. Such terminology may include the wordsspecifically mentioned above, derivatives thereof, and words of similarimport. Similarly, the terms “first”, “second”, and other such numericalterms referring to structures.

As used herein, the terms “front” and “distal” refer to the parts of thesubject apparatus which are located further away from the user (e.g.,surgeon) of the apparatus during an injection operation. As used herein,the terms “rear” and “proximal” refer to the parts of the apparatuswhich are located closer to the user (e.g., surgeon) of the apparatusduring an injection operation.

Apparatus for Mixing Two Gases

With reference to FIG. 1, an embodiment of a gas mixture apparatus 10 acan comprise a measurement control system 110 a, an activation system210 a, and a mixing system 310 a configured to create a mixture of twoor more gases at a desired concentration ratio. The mixing system 310 acan include a pressurized chamber 410 a and a mixing chamber 510 a.

The mixing system 310 a can also include a pressure regulation system toenhance the operation of the mixing system 310 a. In some embodiments,the mixing system 310 a additionally includes a first pressureregulation system 610 a and a second pressure regulation system 710 a.

The measurement control system 110 a can be in the form of a meteringmechanism operatively coupled to any and all devices contained withinthe mixing system 310 a to control certain aspects of the devicescontained therein. In some embodiments, the measurement control system110 a can be a variable and user-operable device such that aspects ofthe device can be modified by the user of the gas mixture apparatus 10a. The activation system 210 a can be operatively coupled to thepressurized chamber 410 a in order to activate operation of the deviceand commence the mixing of gases within the mixing system 310 a.

The pressurized chamber 410 a can contain at least one of the two ormore gases to be mixed within the mixing system 310 a. In someembodiments, the gas contained within the pressurized chamber 410 a canbe at a pressure higher than surrounding ambient conditions.Additionally, the pressurized chamber 410 a can contain gases atconcentrations different from that in the atmosphere. The pressurizedchamber 410 a can be configured such that it is in fluid communicationwith the first pressure regulation system 610 a. In other embodiments,the pressurized chamber 410 a can be in direct fluid communication withthe mixing chamber 510 a. The pressurized chamber 410 a can beconfigured such that it is internally contained within an injectorapparatus. The pressurized chamber 410 a can also be configured suchthat it is external to the injector apparatus. The first pressureregulation system 610 a can be configured to maintain a pre-configuredpressure differential between the pressurized chamber 410 a and themixing chamber 510 a. The mixing chamber 510 a can be configured toreceive gas from the pressurized chamber 410 a either directly or viathe first pressure regulation system 610 a. In some embodiments, themixing chamber 510 a can additionally be configured to receive a secondgas to be mixed from outside the mixing system 310 a such as an externalgas container or the atmosphere. The mixing chamber 510 a can beconfigured such that it is in fluid communication with the secondpressure regulation system 710 a at a mixing chamber 510 a exit point.In other embodiments, the mixing chamber 510 a can be in direct fluidcommunication with the atmosphere at a mixing chamber exit point.Examples of each of these subsystems are described separately below.

In some embodiments, the measurement control system 110 a is configuredto control concentrations of the gas within the gas mixture apparatus 10a. In some embodiments, the measurement control system 110 a isoperatively coupled with the mixing system 310 a. Preferably,measurement control system 110 a is operatively coupled with either thepressurized chamber 410 a or the mixing chamber 510 a such that themeasurement control system 110 a can modify variable aspects of thepressure chamber 410 a and/or the mixing chamber 510 a. In someembodiments, the measurement control system 110 a is capable ofcontrolling characteristics such as, but not limited to, the volume ofgas contained within the mixing chamber 510 a. Other characteristics,such as pressure, are also contemplated as being controllable by themeasurement control system 110 a. Preferably, the measurement controlsystem 110 a is variable such that a user can be able to select adesired concentration ratio of gas that can be expelled from the gasmixture apparatus 10 a. This advantageously allows a user to have only asingle gas mixture apparatus 10 a for a wide range of desiredconcentration ratios. As such, the measurement control system 110 a caninclude user-operable switches such as dials which vary the operation ofcomponents within the mixing system 310 a such as the pressurizedchamber 410 a, the mixing chamber 510 a, the first pressure regulationsystem 610 a, and the second pressure regulation system 710 a.

The pressurized chamber 410 a is configured to store one or more gaseswithin an interior space of the pressurized chamber 410 a for a periodof time prior to mixing the two or more gases in the gas mixtureapparatus 10 a. The conditions within the interior space is configuredto be different than those of atmospheric conditions and therefore theinterior space should generally reduce the release of such gases out ofthe interior space or reduce the entry of non-stored gases into theinterior space until mixing of the two or more gases is to be performed.

In some embodiments, the one or more gases within the interior space areat a higher pressure than ambient atmospheric conditions. Additionally,the one or more gases can also be gases at concentrations different thanthose at ambient atmospheric conditions. In some embodiments, theinterior space can be divided into separate subsections or portions forholding one or more gases. These separate portions of the interior spacecan therefore be kept at different pressures and/or differentconcentrations of gases.

In some embodiments, the gases can additionally be placed in differentstructural units within the interior space. Such structural units can beused to more effectively reduce the release of stored gases and/orreduce the entry of non-stored gases. In some embodiments, the storedgases of the pressurized chamber 410 a are pre-loaded from the time ofmanufacture. In other embodiments, it is contemplated that the contentsof the pressurized chamber 410 a can be loaded by a user of the gasmixture apparatus 10 a. For example, the stored gases can be containedin a removable cartridge-like device which can advantageously facilitatethe replacement of such gases.

In some embodiments, the activation system 210 a is configured toactivate the operation of the gas mixture apparatus 10 a and commencethe process of mixing the two or more gases within the mixing system 310a. As such, the activation system 210 a is operatively coupled to themixing system 310 a and can be coupled to both the mixing chamber 310 aand the pressurized chamber 410 a. The activation system can cause thepressurized chamber 410 a to activate and release gases containedtherein into the mixing chamber 510 a. In some preferred embodiments,the activation system 210 a can cause the pressure within thepressurized chamber 410 a to increase such that the first pressureregulation system 610 a is activated thereby allowing fluid flow fromthe pressurized chamber 410 a into the mixing chamber 510 a. Theactivation system 210 a can include a device configured to activate aseparate portion of the pressurized chamber 410 a that contains higherpressure gas than the remainder of the pressurized chamber 410 a suchthat the pressure within a separate section of the pressurized chamber410 a increases. In a preferred embodiment, the activation system 210 acan cause a sealed device within the mixing chamber 510 a to burstthereby increasing the pressure throughout the pressurized chamber 410a. In such embodiments, the activation system 210 a can include apuncturing device capable of bursting the seal. Use of an activationsystem 210 a provides advantages by allowing the gas mixture apparatus10 a to potentially be pre-filled prior to use and safely stored.

The activation system 210 a can also be operably coupled to the mixingchamber 510 a allowing a user to manually vary certain aspects of thedevice. In some embodiments, the activation system 210 a can be used tomodify the volume of the mixing chamber 510 a. The activation system 510a can also be used to modify the pressure of the mixing chamber 510 a.

In some embodiments, the first pressure regulation system 610 a isconfigured to serve as a separation mechanism between both thepressurized chamber 410 a and the mixing chamber 610 a. The firstpressure regulation system 610 a can activate upon reaching apre-configured pressure differential between both the pressurizedchamber 410 a and the mixing chamber 510 a. In some preferredembodiments, the first pressure regulation system 610 a can be comprisedof at least one valve assembly. The valve assembly can open whenpressure within a portion of the pressurized chamber 410 a is higherthan the pressure in the mixing chamber 510 a. The valve assembly can bea check valve, clack valve, non-return valve, or one-way valve. Suchvalves can also include ball check valves, diaphragm check valves, swingcheck valves, stop-check valves, lift-check valves, in-line checkvalves, and duckbill valves. Other pressure regulation mechanisms canalso be used. Additionally, it is contemplated that first pressureregulation system 610 a can also be activated by other means other thanpressure differentials across the system 610 a.

In some embodiments, the mixing chamber 510 a is configured to serve asa space within which the two or more gases can be mixed to obtain adesired concentration ratio of the gases. The mixing chamber 510 a canbe such that the volume can be variable and adjustable based upon use ofthe activation mechanism. The mixing chamber 510 a can receive the gasesto mix solely from the pressurized chamber or from gases alreadyexisting within the mixing chamber 510 a. The mixing chamber 510 a canalso receive gases from secondary sources. In some embodiments, themixing chamber 510 a can receive air from the atmosphere to mix with thegases received from the pressure chamber 310 a and/or gases alreadyexisting within the mixing chamber 510 a.

In some embodiments, the second pressure regulation system 710 a isconfigured to serve as a separation mechanism between both the mixingchamber 510 a and the surrounding atmosphere. The second pressureregulation system 710 a can activate upon reaching a pre-configuredpressure differential between both the mixing chamber 510 a and thesurrounding atmosphere. In some preferred embodiments, the secondpressure regulation system 710 a can be comprised of at least one valveassembly. The valve assembly can open when pressure in the mixingchamber 510 a is higher than the pressure in the surrounding atmosphere.The valve assembly can be a check valve, clack valve, non-return valve,or one-way valve. Such valves can also include ball check valves,diaphragm check valves, swing check valves, stop-check valves,lift-check valves, in-line check valves, and duckbill valves. Otherpressure regulation mechanisms can also be used. Additionally, it iscontemplated that second pressure regulation system 710 a can also beactivated by other means other than pressure differentials across thesystem 710 a.

Operational Overview

With reference to FIGS. 2A-2D, the operation of an embodiment of a gasmixture apparatus 10 b is illustrated. With reference to FIG. 2A, theapparatus 10 b can be in an initial phase with the activation system 210b in a first or “closed” position. At this time, the user of the devicecan use the measurement control system 110 b to select a desiredconcentration of gas for the injectable volume. Once the selection hasbeen made, the user can then move the activation system 210 b into asecond or “open” position thereby causing the system to activate andcommencing the mixing process.

During this first phase of operation, as shown in FIG. 2B, gas containedwithin the pressurized chamber can be released and, in embodimentscontaining a first pressure regulation system, the first pressureregulation system can open in response to a change in pressure withinthe chamber. As such, fluid can flow from the pressurized chamber intothe mixing chamber 510 b thereby causing an increase in the volume ofthe mixing chamber 510 b. However, due to components of the measurementcontrol system 110 b, the mixing chamber 510 b can reach a first volumeand cannot expand beyond this first volume. This first volume can be setbased on the desired concentration of the injectable volume. During thisfirst phase of operation, excess gas can also be bled from the mixingchamber 510 b via the second pressure regulation system 710 b. Once themixing chamber has reached this first volume, the first phase ofoperation is complete and the second phase of operation begins.

During the second phase of operation, the mixing chamber 510 b canremain at the first volume while pressure within the mixing chamber 510b is bled from the system via the second pressure regulation system 710b. By overfilling the mixing chamber 510 b with the desired gas, andthen bleeding off that gas, this helps to ensure that a significantamount of atmospheric gas within the mixing chamber 510 b, which mayhave been contained in the mixing chamber 510 b prior to activation, issubstantially purged from the mixing chamber 510 b and displaced by thegas originally contained in the pressurized chamber. Once the pressurewithin the mixing chamber 510 b has reached a configured value based onthe configuration of the second pressure regulation system 710 b,bleeding of the gas within the mixing chamber 510 b ceases and thesecond phase of operation is complete.

During a third phase of operation, as shown in FIG. 2C, an attachment760 can be added to the system which can force the second pressureregulation system 710 b to remain open. This attachment can be a filterto remove bacteria to sterilize air, an infusion cannula or a syringeneedle. This opening of the second pressure regulation system 710 bcauses gas within the mixing chamber 510 b to reach ambient pressure.Once sufficient time has elapsed for the gas to reach ambient pressure,the user can then set the activation system 210 b to the first or“closed” position thereby unlocking the measurement control system 110b. The user can then manually expand the volume of the mixing chamber510 b to the injectable volume. In some embodiments, the measurementcontrol system 210 b can stop expansion of the volume of the mixingchamber 510 b once the injectable volume is reached. Once the thirdphase is complete, the attachment can be removed such that the secondpressure regulation system 710 b can isolate the mixed gas from thesurrounding atmosphere to reduce or prevent dilution of the mixed gas.

One significant advantage of the operation of the apparatus 10 b is thatthe entire process can be performed by a single individual within thesterile field. Furthermore, the process is substantially automated suchthat the user need only set the measurement control system 210 b to aproper setting and the apparatus 210 b will automatically perform asubstantial majority of the remaining steps. Additionally, the stepsautomatically performed by the apparatus 10 b are those which cannormally be most-prone to error such as measuring proper volumes toachieve a desired concentration thereby significantly reducing the riskof obtaining an incorrect concentration of gas in the injectable volume.Inadvertent dilution of the gas with the surrounding atmosphere at theconclusion of the second and third phases of the operation can bereduced or prevented with the incorporation of the second pressureregulation system 710 b.

In other embodiments, a fewer or greater number of phases of operationcan be performed. In some embodiments, only a single phase of operationcan be performed. For example, the pressurized chamber 410 a can containa gas at a pre-set concentration level. During the single phase ofoperation, the user can activate the apparatus 10 b such that a gas orfluid flows from the pressurized chamber 410 a and into a secondchamber, such as the mixing chamber 510 a, until the chamber reaches aconfigured volume. The gas or fluid can also be expelled or bled offusing a pressure regulation system until a desired pressure is achievedwithin the chamber. After expelling the gas, the apparatus 10 b can beready for use. As should be apparent to one of skill in the art, in suchan embodiment, little to no mixing may in fact be performed.

System Overview

With reference to FIG. 3, components of an embodiment of a gas mixtureapparatus 10 b are shown which comprise a measurement control system 110b, an activation system 210 b, a pressurized chamber 410 b, a mixingchamber 510 b, a first pressure regulation system 610 b, and a secondpressure regulation system 710 b. The measurement control system 110 bcan comprise a metering dial 120 and a plunger body 160 which can beinserted into the metering dial 120. The activation system 210 b cancomprise an actuation rod 220 and activation switch 260. The activationsystem 210 b can be operatively coupled to the measurement controldevice 110 b to control the operation of the gas mixture apparatus 10 b.The activation system 210 b can be inserted into the plunger body 160.

The pressurized chamber 410 b can be comprised of a housing 420, acanister 436 containing a gas, a release mechanism 444 to release thegas contained within the canister 436, a filter 448 to reduce the amountof non-gas or bacteria material flowing out of the housing 420, and aplunger seal 460. The mixing chamber 510 b can be comprised of a syringebody 520. The first pressure regulation system 610 b can comprise avalve body and associated valve components. The second pressureregulation system 710 b can also comprise associated valve components.

Measurement Control System and Activation System

With reference to FIG. 4, an embodiment of a combined measurementcontrol system 110 b and activation system 210 b is shown. Themeasurement control system 110 b can comprise a metering dial 120 and aplunger body 160. The activation system can comprise an actuation rod220 (shown in FIG. 7) and an activation switch 260.

With reference to FIGS. 5A and 5B, an embodiment of a metering dial 120of the gas mixture apparatus 10 b is shown which is configured to allowa user of the apparatus 10 b to selectively vary the concentration of aninjectable volume. The metering dial 120 is comprised of at least twostructural components—a metering body 122 and a metering cap 124 whichcan be coupled to the metering body 122 so as to allow the metering dial120 to be reversibly attached to another component of the apparatus 10b. This can advantageously facilitate assembly of the apparatus and, insome embodiments which are reusable, can facilitate disassembly forresterilization. In some embodiments, the metering cap 124 can bereversibly attached to the metering body 122 using fasteners such asscrews, rivets, clips, and other fastening mechanisms known in the art.Attachment of the metering cap 124 to the metering body 122 can form anannular slot 126 and an annular lip 128 such that the metering dial 120can be attached to another component of the apparatus 10 b. For example,the annular slot 126 and annular lip 128 can correspond to a flange 526located on the syringe body 520.

The metering body 122 can have a generally cylindrical member 130 with aflange 132 at the top end and a channel 134 substantially centered onthe cylindrical member 130 and running throughout the entire meter body122. Since the meter body 122 is configured to control the concentrationof the gas in the injectable volume, the meter body 122 can includemetering indicators 136 along a surface viewable by a user of theapparatus 10 b in a fully assembled state. In the illustratedembodiment, the metering indicators 136 are located on a top surface ofthe flange 132 although any location which can be viewed by the user canbe used. The metering indicators 136 can provide the user of the devicewith information regarding the operation of the apparatus 10 b. In theillustrated embodiment, the metering indicators 136 show a range ofnumbers from 18, 19, 20, 21, and 22 corresponding to concentrations ofsulfur hexafluoride (SF₆) which would be produced in the injectablevolume if the apparatus 10 b is activated. As should be apparent to oneof skill in the art, the ranges used can depend upon the gas used andthe application for the gas. Furthermore, in some embodiments, thisrange can be further divided to provide enhanced control over thedesired concentration.

The metering body 122 can have slots 138, rails 140, and variable stops142 corresponding to the metering indicators 136. In the illustratedembodiment, the metering body 122 has five separate slots 138 locatedalong an inner surface of the channel 134 which correspond to the fiveinteger values stated above. In other embodiments, the metering body 122can have fewer or greater slots than the number of values provided bythe metering indicators 136.

Corresponding with each of these slots 138 are variable stops 142 whichextend inwardly from the slots 138. As illustrated above, these variablestops 142 can extend from the top surface of the flange 132 to a setdistance towards the bottom end of the tubular body 130. In someembodiments, the variable stops 142 need not extend from the top surfacebut instead are minor protrusions at set distances towards the bottomend of the cylindrical member 130. These variable stops 142 areconfigured to interact with components contained in the plunger body 160such as a latch 228, or the plunger body 160 itself to control theexpansion volume of the mixing chamber 510 b during a first and secondphase of operation by limiting the rearward extension of the plungerbody 160 during these phases (see FIG. 2B). As such, the variable stops142 extend different distances depending upon the concentration to whichthe stop 142 corresponds. For example, a concentration of 21 percentextends a lesser distance than a concentration of 20 percent. As such,when a concentration of 21 percent is chosen, the plunger body 160 canbe allowed to extend rearwardly a greater distance thereby allowing agreater expansion of the mixing chamber 510 b during the first phase ofoperation. Therefore, as should be apparent, the variable stops 142 areused to control the first expansion volume of the first phase ofoperation.

On both sides of slots 138 are rails 140 which extend inward from aninner surface of the channel 134. In some embodiments, the rails 140extend inwardly from the inner surface of the channel 134 a greaterdistance than the variable stops 142. The rails 140 can be configured toprevent the apparatus 10 b from switching to a different concentrationvalue once the apparatus 10 b has been activated. This can beparticularly important in applications where a specific concentration ofgas can be necessary and any minor change in this value can havesignificantly adverse effects. In the illustrated embodiment, the rails140 are configured to substantially reduce the likelihood that theplunger body 160 will rotate to a different variable stop 142 during atleast the first two phases of operation. In certain embodiments, theserails can be removed if a constantly variable metering device isdesired. In such an embodiment, the variable stop 142 could instead havea ramp shape rather than have multiple steps.

Metering body 122 can additionally include a ratchet pawl 144 along aninner surface of channel 134 which extends inwardly toward the center ofthe channel 134. The ratchet pawl 144 can be hinged and configured suchthat the ratchet pawl 144 is movably deformable and provides resistanceduring deformation. This ratchet pawl 144 can correspond to featureslocated on the plunger body 160 to facilitate proper orientation withrespect to the selected concentration. Such a mechanism can additionallyprovide tactile feedback to a user of the device indicating that theproper alignment has been achieved. This tactile feedback canadvantageously reduce the likelihood of activation in an improperorientation. Other types of feedback mechanisms and alignment mechanismscan also be used.

With reference to FIG. 6, an embodiment of a plunger body 160 is shownwhich comprises a generally tubular frame 162, a handle 164 at one endof the plunger body 160, a selector ring 166 located therebetween, and achannel 168 centered on the tubular frame 162 and running throughout theentire length of the plunger body 160. The tubular frame 162 isconfigured to be slidably translatable and partially slidably rotatablewithin the channel 134 of the metering dial 120. The tubular frame 162has a retention mechanism 170 in the form of a clip which is hingedlyattached to the tubular frame 162. The retention mechanism 170 can beconfigured to retain a component such as a housing 420 of thepressurized chamber 410 b. The retention mechanism 170 advantageouslyallows the component to be attached without the use of tools therebyfacilitating the process of assembling the entire device. Additionally,the retention mechanism 170 can also be configured such that thecomponent can be removed from the tubular frame 162 thereby allowing theapparatus 10 b to be reused or, in other embodiments which allow forreuse of the apparatus 10 b, facilitating the process of resterilizationif such a process is used for the device. Other types of retentionmechanisms can also be used in lieu of the clips shown in theillustrated embodiment and can include fasteners such as screws.

Tubular frame 162 can additionally comprise a guard 172 which extendsoutward from the outer surface of the tubular frame 162. The guard 172can run from the bottom end of the tubular frame 162 to a distancetoward the top end of the tubular frame 162. The guard 172 is configuredto fit within the slots 138 and rails 140 located along the innersurface of the channel 134 of the metering body 122. As such, the guard172, when positioned between the rails 140, can prevent the plunger body160 from rotating. This advantageously can prevent the plunger body 160from moving to a different variable stop 142 after commencing the firstphase of operation and thereby reduce the risk of an improperconcentration in the injectable volume. The guard 172 is preferablysized such that, when the plunger body 160 is fully inserted, the guard172 is only slightly below the rails 140 such that the plunger body 160can rotate freely to different concentration values during the initialphase of operation (see FIG. 2A). However, because the guard 172 is onlyslightly below the rails 140, once extended a short distance, the guard172 can become locked within the selected rail 140. This positioningadvantageously allows the guard 172 to lock shortly after activation ofthe apparatus 10 b. Furthermore, the guard 172 preferably extendsoutward from the tubular frame 162 only a sufficient distance such thatit can contact the rails 140 but not enough such that it contacts thevariable stops 142 located between the rails 140. This can thereforeallow the guard 172 to not be interfered by the variable stops 142during operation.

Tubular frame 162 can additionally comprise a latch aperture 174configured to allow a latch 228 located on the activation rod 220 toprotrude outward from the tubular frame 162. The latch aperture 174 ispreferably centered just above the top-most portion of the guard 172. Aswill be discussed in detail below, in a first or “closed” position, thelatch 228 can not extend beyond the guard 172 and thus would not contacta variable stop 142 (see FIG. 8A). When in a second position, the latch228 can extend outward from the tubular frame 162 beyond the guard 172such that the latch 228 can contact the variable stops 140 therebypreventing further extension of the plunger body 160 while the latch isin the second position (see FIG. 8B). In some embodiments, the latchaperture 174 can be placed such that, if the plunger body 160 isimproperly oriented within the metering dial 120 during an initial phaseof operation (shown in FIG. 2A), the latch 228 can be prevented fromextending outward into the second or “open” position by a rail 140 ofthe metering dial 120. This can advantageously prevent the apparatus 10b from activating when improperly oriented.

Tubular frame 162 can additionally include ratchet slots 176 in the formof cutouts located along its outer surface. The ratchet slots 176 areconfigured to receive the ratchet pawl 144 of the metering body 122thereby providing a mechanism for ensuring that the plunger body 160 isproperly oriented within the metering body 122 by providing resistanceagainst rotation when the pawl 144 is received within one of the ratchetslots 176. Furthermore, advantageously, at each point where the ratchetpawl 144 is received within the ratchet slots 176, a user of theapparatus 10 b can also receive tactile feedback when the plunger body160 is properly oriented within the metering body 122.

Selector ring 166 can be an annular protrusion extending from the outersurface of the tubular frame 162. The selector ring 166 can additionallyinclude a selector indicator 178 which can take the form of a minorprotrusion located on the selector ring 166. Selector indicator 178 cancorrespond to the metering indicators 136 located on the metering body122 to indicate the concentration level that will be obtained when theplunger body 160 is oriented in that position. Such a system canadvantageously provide a user of the device with easily viewedinformation regarding the selected concentration level. The selectorindicator 178 can advantageously be colored to facilitate use of theapparatus 10 b.

The handle 164 can extend in two opposite directions in a radialdirection from the longitudinal axis of the tubular frame 162. Handle164 can be shaped such that a user of the apparatus 10 b can contact thehandle 164 and use the handle to either further extend the plunger body160 rearward and out of the apparatus 10 b or further depress theplunger body 160 frontward into the apparatus 10 b. Handle canadditionally include a pin aperture 180 for receiving a couplingmechanism for the activation switch 260. The activation switch 260 canthereby rotate about the coupling mechanism in order to operate theactuation rod 220 located within the plunger body 160.

With reference to FIG. 7, an embodiment of an activation system 210 b isshown which comprises an actuation rod 220 and an activation switch 260.The actuation rod 220 has a generally elongate body with an actuator pin222 at a first end, an actuator stem 224 at a second end, and a latchmovement portion 226 located in an intermediate portion. The actuatorpin 222 is configured to be received within a housing 420 of thepressurized chamber 410 b and activate the release of gas containedtherein when in a second or “open” position. The actuator stem 224 isconfigured to abut and follow the contoured surface 262 of the activatorswitch 260. The actuator stem 224 is also preferably shaped such thatthe cross-sectional profile matches the cross-sectional profile in a topportion of the channel 169 (as shown in FIG. 8) located near the handle164 of the plunger body 160. Preferably, the cross-sectional profile isnot substantially circular such that the actuator rod 220 issubstantially prevented from rotating within the channel 168 of theplunger body 160. The latch movement portion 226 is shaped such that thelatch 228 is translated when the latch 228 slidably translates along thelatch movement portion 226 of the actuation rod 220. As such, the latch228 has an aperture 230 which has a cross-sectional shape similar tothat of the cross-sectional shape of the latch movement portion 226.

The activator switch 260 is configured to translate the actuator rod 220through the plunger body 160 and through the housing 420 of thepressurized chamber 410 b to activate the release of gas containedtherein. As such, the activator switch 260 can be a cam with a contouredprofile 262 along the surface configured to contact the actuator stem224. Activator switch can also have an aperture 264 configured toreceive a pin 266 such that the activator switch 260 can rotate aboutthe pin 266. In the illustrated embodiment, the activator switch 260 isshown in a first or “closed” position. In this first position, thedistance between the pin 266 and the contoured surface 262 in contactwith the actuator stem can be a reduced distance such that the actuatorrod remains in a first or “closed” position. However, when rotated aboutthe pin 266 to a second or “open” position, the distance between the pin266 and the contoured surface 262 in contact with the actuator stem 224can be an increased distance thereby translating the actuator rod 220 toa second or “open” position further into the housing 420 of thepressurized chamber 410 b. As will be discussed in greater detail withrespect to FIGS. 10 and 11 below, movement into the second or “open”position can be configured to release gas in the pressurized chamber 410b. The activator switch 260 can preferably be any type of switch thatcan remain in a first or second position without the user needing tomaintain the switch in that position. In the illustrated embodiment, arotating lever is used. Other switches can also be used such as a screw,latch, spring loaded pin, or any other switch known in the art.

With reference to FIGS. 8A and 8B, an illustration of the operation ofthe activation system 210 b is shown which includes some components ofthe measurement control system 110 b and the activation system 210 b. Asshown here, the latch 228 is contained within the latch aperture 174such that the latch cannot translate toward a front end or rear end ofthe plunger body 160. As such, when the actuator rod 220 translates in afrontward or rearward direction, the latch 228 must follow the profileof the latch movement portion 226 of the actuator rod 220. As such, thisprovides the advantage of coupling movement of the latch 228 in thesecond position when the activator switch 260 and thus the actuator rod220 are in a corresponding second position. Furthermore, becausemovement of the latch 228 is coupled with movement of the otheractivator switch 260 and actuator rod 220, if the latch 228 is preventedfrom moving into the second position, the activator switch 260 andactivator rod 220 are also prevented from moving into the secondposition. Note that, as described above, while in the second or “open”position, the latch 228 can protrude from the plunger body 160 therebyrestricting extension of the plunger body 160 as shown in FIG. 8B.

Pressurized Chamber and First Pressure Regulation System

With reference to FIG. 9, an embodiment is shown including somecomponents of both the activation system 210 b, the pressurized chamber410 b of the mixing system 310 b, and the first pressure regulationsystem 610 b of the mixing system 310 b. As illustrated, the pressurizedchamber 410 b can have a housing 420 with an annular slot 422 locatednear a first end of the housing 420. The annular slot 422 can beconfigured to receive the retention mechanism 170 located on the plungerbody 160. Housing can also have a plunger seal 460 located at a secondend of the housing 420. The plunger seal 460 is configured to provide anairtight seal for defining the mixing chamber 510 b.

With reference to FIG. 10, which is a sectional view of the pressurizedchamber 410 b and the first pressure regulation system 610 b. Thehousing 420 has a generally cylindrical body with an annular slot 422located at the first or rearward end and a conical or frusto-conicalsurface 424 located at the second or frontward end corresponding to theshape of the plunger seal 460. Housing 420 can additionally be shapedsuch that it has an annular protrusion 426 and an annular slot 428configured to receive a lip 462 of the plunger seal 460. Thisconfiguration advantageously ensures that the plunger seal 460 remainsconnected to the housing 420 and forms a seal to prevent the leakage ofany gas contained in the housing body 420. It can be preferable that thelip 462 of the plunger seal 460 fit snugly within the annular slot 428of the housing 420 to provide an enhanced seal. An interior space 430 issubstantially enclosed by the housing 420 and can be separated into afirst separate portion 432 and a second separate portion 434. Containedwithin the second separate portion 434 of the housing 420 can be a thirdseparate portion in the form of a structural unit such as a canister436. This canister can contain the gases for mixing into the mixingchamber 510 b. Provision of the gases in a canister is advantageous asit facilitates manufacturing of the apparatus 10 b as it can allow thecanisters to be manufactured separately from other components of thepressurized chamber 410 b. In some embodiments where the apparatus 10 bis reusable, cartridges can be replaced.

The canister 436 has a first or rearward end in contact with theactuator pin 222 and a sealed second or frontward end 437. At one end ofthe canister 436 is a seal 438 which substantially reduces leakage ofany gas from the first separate portion 432 to the second separateportion 434. This advantageously reduces the likelihood of gases fromleaking out of the actuator aperture 440 and out of the apparatus 10 b.

The housing can also include a biasing mechanism 442, such as a spring,which exerts a force on the seal in a direction away from the second endof the housing 420. In the illustrated embodiment, the biasing mechanism442 is located in the first separate portion 432. This reduces thelikelihood of the canister 436 moving into the first separate portion432 and potentially releasing the gas contained therein without havingbeen activated by the user. Furthermore, biasing mechanism 442 can alsoprovide a counter-force against activation such that a user can notaccidentally activate the device. It is preferable that the biasingmechanism 442 be configured to exert a sufficient force such that, afterthe first and second phases of operation are complete and the activationswitch 160 is returned to a first or “closed” position, the biasingmechanism 442 exerts sufficient force such that actuator rod 220 isreturned to its first or “closed” position thereby causing the latch 228to return to its first or “closed” position. Once latch 228 returns toits first or “closed” position, the extension of the plunger body 160 isno longer limited and the third phase of operation can commence. If thebiasing mechanism 442 does not exert sufficient force on the actuatorrod 220, entering into the third phase of operation could be madesignificantly more difficult.

Housing can also have a release mechanism 444, such as a needle or apilot tip as illustrated in this embodiment of the apparatus 10 b, whichcan be configured to puncture the sealed second end 437 of the canister436 to release gas into the first separate portion 432 through therelease mechanism 444 due to a channel 446 running axially throughrelease mechanism 444. Due to the high pressure in the first separateportion 432, the first pressure regulation system 610 b can openallowing the gas to escape to the front of the plunger seal 460 and intothe mixing chamber 510 b. In some embodiments, a filter 448 can beplaced along the flow path such that there is a reduced likelihood offoreign materials entering into the mixing chamber 510 b. This can beparticularly important when the gas can be placed into areas highlysensitive to the presence of foreign materials such as bodily cavities.The presence of foreign materials can cause infection or other harm. Insome embodiments, the filter 448 can be configured to filter outbacteria to sterilize the air.

Plunger seal 460 is configured to partially define the injectable volumeof the mixing chamber 510 b by creating a seal for the mixing chamber510 b. Plunger seal 460 can have a generally cylindrical body withannular protrusions 464 configured to contact an inner surface of themixing chamber 510 b and a conical or frustoconical face 466 at afrontward end. The frustoconical face 466 can additionally comprise anaperture 468 centered about the cylindrical body configured to receivecomponents of the first pressure regulation system 610 b. Furthermore,the body can also have an opening 470, defined by the lip 462, on therearward end configured to receive the housing 420.

With continued reference to FIG. 10, an embodiment of the first pressureregulation system 610 b is shown in a first or “closed” position. Thefirst pressure regulation system 610 b can comprise a valve body 620comprising multiple apertures 622 at one end, a valve stem 624 runningthrough the valve body 620 with a seat 626 at a rear end configured tocontact the biasing mechanism 628 and a head 630 at a front endconfigured to contact a sealing ring 632. During operation, the biasingmechanism 628 can exert a biasing force against the seat 626 in arearward direction such that the head 630 is biased against the sealingring 632 and valve body 620 thereby reducing or preventing the flow ofgas through the valve body 620 and ultimately into the mixing chamber510 b. Due to the orientation of the biasing mechanism 628, the firstpressure regulation system 610 b remains closed until pressure withinthe pressurized chamber 410 b exceeds a threshold value. This thresholdvalue can be configured by changing the amount of force necessary tocompress the biasing mechanism 628.

With reference to FIG. 11, an embodiment of the first pressureregulation system 610 b is shown in an “open” position during the firstand second phase of operation. During these phases, pressure within thepressurized chamber 410 b can exceed the pressure within the mixingchamber 510 b. In some preferred embodiments, the difference in pressureis substantial. Due to this pressure differential, sufficient force isplaced upon the valve components causing the biasing mechanism 628 to beovercome thereby allowing gas to flow out of the valve body 620 and intothe mixing chamber 510 b.

This configuration for the first pressure regulation system 610 b isadvantageous due to the multiple phases of operation of the apparatus 10b. During the first and at least part of the second phase of operation,the pressure differential causes the valve to remain open. However, oncethe pressure differential is insufficient to overcome the thresholdvalue, the valve remains in a closed position preventing any additionalgas from flowing into the mixing chamber and potentially disrupting thecalculated pressures/concentrations.

With reference to FIG. 12, an embodiment of a mixing chamber 510 b isshown comprising a syringe body 520, a second pressure regulation system710 b, and various components of the above-mentioned systems. Syringebody 520 has a cylindrical body, an aperture 522 at the rear end, and athreaded nozzle 524 at the front end. Syringe body also has flange 526configured to be engaged with the metering device 120. The mixingchamber 510 b can be defined by the inner walls of the syringe body 520and the plunger seal 460. Furthermore, the syringe body can includeindicators 528 along its outer surface corresponding to a chosenconcentration. These indicators 528 can advantageously provide visualconfirmation to the user of the selected concentration.

With reference to FIG. 13, an embodiment of the second pressureregulation system 710 b is shown comprising a valve body 720 which caninclude a ball 722, a biasing mechanism 724, a seat 726, and a sealingmechanism 728. The second pressure regulation system 710 b can alsocomprise a second biasing mechanism 730 and a pin actuator 732. Thevalve body 720 can be translatable within the interior space 734 nearthe nozzle 524 of the syringe body 520. In some embodiments, due to thesecond biasing mechanism 730, the valve body 720 is translated such thata flange 735 of the valve body 720 is pressed against the inner lip 736of the nozzle 524. Furthermore, biasing mechanism 724 can seal flowthrough the valve body 720 until a sufficient force is placed on theball 722 to overcome the biasing force. This can occur when the pressuredifferential between the mixing chamber 510 b and the atmosphere isbeyond a threshold value.

During operation, the second pressure regulation system 710 b is openedduring a first and second phase of operation due to the increasedpressure contained in the mixing chamber 510 b. Once the pressuredifferential is insufficient to cause valve body 720 to open, the secondphase of operation is complete and the user can proceed to the thirdphase of operation.

With reference to FIG. 14, an embodiment of the second pressureregulation system 710 b is shown with an attachment 760 comprising afilter. The attachment 760 has a first open end 762 with a flange 764configured to engage with the threads on the interior of the threadednozzle 524, a second open end 766, and a filter element 768 locatedtherebetween. As such, gas can pass from the first open end 762 to thesecond open 766 and advantageously be filtered in the process whichreduces the risk of any harmful materials enter the mixing chamber 510b. In some embodiments, the inner surface of the first open end 762tapers when moving towards the second open end 766 such that the shapecorresponds to the shape of valve body 720. As the attachment 760 isthreaded into the threaded nozzle 524, the attachment 760 engages thevalve body 720 and translates the valve body 720, against the biasingforce of the second biasing mechanism 730 towards the rear end of thesyringe body 520. This causes the ball 722 to engage the pin actuator732 thereby causing the valve body 720 to open allowing gas within themixing chamber 510 b to reach ambient pressure. This configuration isadvantageous as it allows the mixing chamber 510 b to be furtherexpanded at ambient pressure and simultaneously filtering air drawn intothe mixing chamber 510 b. In this position, the third phase of operationcan therefore be performed. Once the third phase of operation iscompleted, the attachment 760 can be removed. Due to the force of thesecond biasing mechanism 730, the valve body 720 can be translated awayfrom pin actuator 732 such that the valve body 720 remains closed untila user decides to inject the gas.

Embodiment of Measurement Control System and Activation System

FIGS. 15-30 illustrate additional embodiments of components of ameasurement control system of the apparatus.

FIGS. 15A and 15B illustrate an embodiment of a metering dial 820 whichcan be configured to allow a user of the device to select aconcentration of fluid for an injectable volume. Similar to otherembodiments, the metering dial 820 can include two components such as ametering body 822 and a metering cap 824 which can be removably attachedto the metering body 822. As with other embodiments of a metering dialand similar metering devices, such as metering dial 120, the removableattachment can advantageously facilitate the assembly of the apparatus.Furthermore, in some embodiments, the removable attachment can allow fordisassembly such that the apparatus can be reduced to individualcomponents to facilitate resterilization of some or all of thecomponents of the apparatus. As with other embodiments, the metering cap824 can be reversibly attached to the metering body 822 using fastenerssuch as screws, rivets, clips, and other fastening mechanisms known inthe art. In other embodiments, the metering body 822 and metering cap824 can be irremovably attached using devices and methods such asadhesives, welding, and the like. Such embodiments can provide anadvantage of reducing the likelihood of tampering. Attachment of themetering cap 824 to the metering body 822 can form an annular slot andan annular lip such that the metering dial 820 can be attached toanother component of the apparatus. In some embodiments, the annularslot and the annular lip can correspond to corresponding features, suchas a flange and lip, located on a syringe on which the metering dial 820is placed.

With continued reference to FIG. 15A and FIG. 15B, the metering body 822can have a generally cylindrical member 830 with a flange 832 located attop portion of the metering body 822. The metering body 822 can includea channel 834 substantially centered on the cylindrical member 830 andrunning throughout the entire metering body 822. In some embodiments,the generally cylindrical member 830 can be sized and shaped to bereceived within a channel of another component of the apparatus. Forexample, in some embodiments, the metering body 822 can be receivedwithin a channel of a syringe to which the metering dial 820 isattached. In some embodiments, such as that illustrated in FIG. 15A, thegenerally cylindrical member 830 can include additional surfacefeatures, such as an increased diameter portion 831, which canpotentially be keyed to the device into which it is inserted.

As with other embodiments of metering dials or similar meteringmechanisms, this embodiment can also include metering indicators 836located along a surface of the metering body 820. In this illustratedembodiment the metering indicators 836 are located on a top surface ofthe flange 832 although any other viewable location can be used such as,for example, along the perimeter portion of the flange 832. In theillustrated embodiment, the metering indicators 836 show a range ofnumbers from 18, 19, 20, 21, and 22 corresponding to concentrations ofsulfur hexafluoride (SF₆) which can be produced in an injectable volumeof the assembly. As should be apparent to one of skill in the art, theranges used can depend upon the gas used and the application for thegas. In some embodiments this range can be further divided to providegreater precision and control over the desired concentrations.

As with other embodiments of metering dials and other meteringmechanisms, the metering body 822 can have slots 838, rails 840, andvariable stops corresponding to the metering indicators 836. As moreclearly shown in FIG. 15B, the metering body 822 can have five separateslots 838 located along an inner surface of the channel 834 whichcorrespond to the five metering positions 18, 19, 20, 21 and 22. Inother embodiments, the metering body 822 can have fewer or greater slotsthan the number of values provided by the metering indicators 836.Corresponding with each of these slots 838 can be variable stops whichextend inwardly from the slots 838. These variable stops can extend fromthe top surface of the flange 832 to a set distance towards the bottomend of the generally cylindrical member 830. As should be appreciated byone of skill in the art, the variable stops need not extend from the topsurface. For example, in some embodiments, the variable stops can beprotrusions at set distances towards the bottom end of the tubular body830.

The operation of the variable stops of the illustrated embodiment of themetering dial 820 can be similar to that of other embodiments ofmetering dials and metering mechanisms. The variable stops can beconfigured to interact with components contained within the plunger body860, such as a latch 928 or similar protruding structure, to controlexpansion of a chamber for an injectable volume during at least somephases of operation. In some embodiments, the variable stops can performthis task by limiting the rearward extension of the plunger body 860during different phases. As such, the variable stops extend differentdistances depending upon the concentration to which the stopcorresponds.

With continued reference to FIGS. 15A and 15B, both sides of slots 838can be bounded by rails 840 which extend inwardly from an inner surfaceof the channel 834. In some embodiments, the rails 840 can extendinwardly from the inner surface of the channel 834 a greater distancethan the stops. The rails 840 can be configured to prevent the apparatusfrom switching to a different concentration value once activated. In theillustrated embodiment, the rails 840 are configured to substantiallyreduce the likelihood that the plunger body 860 will rotate to adifferent variable stop during at least the first two phases ofoperation. In certain embodiments, the rails 840 can be removed if aconstantly variable metering device is desired. In such circumstancesother mechanisms can be used to prevent or otherwise significantlyreduce the likelihood that a different concentration value will bechosen after the device has been activated.

As illustrated more clearly in FIG. 15B, metering body 822 canadditionally include along an inner surface of the channel 834 notches,indentations, divots, recesses, or similar structures 842 located alongan inner surface of the channel 834 opposite the slots 838 and rails840. In other embodiments, the notches 842 can be located at othersuitable locations on the metering dial 820. These notches 842 cancorrespond to features located on other components of the apparatus toform a ratcheting mechanism. For example, the notches 842 can correspondto a ratcheting member 886 (shown on FIGS. 21-23) located on the plungerbody 860. As such, the ratcheting mechanism can be configured toadvantageously provide a user with tactile feedback when the plungerbody 860 has been rotated to a selectable concentration. As such, a userof the device can be less likely to accidentally have the plunger body860 in an inoperable position when the gas assembly is activated.Furthermore, the ratcheting mechanism can also provide a thresholdresistance against rotation from one concentration to a secondconcentration. In such embodiments, the ratcheting mechanism can therebyadvantageously reduce the likelihood of unintentional rotation from oneconcentration to a second concentration. Other types of feedbackmechanisms and alignment mechanisms can also be used to provide thistactile feedback.

With reference to FIG. 16, an embodiment of a plunger body 860 is shownwhich can include a generally tubular frame 862, a handle 864 at one endof the plunger body 860, a selector member 866 located there between,and a channel 868 centered on the tubular frame 862 which can runthroughout the entire length of the plunger body 860 or which can runthroughout at least a part of the length of the tubular frame 862. Thetubular frame 862 can be configured to slidably translate and slidablyrotate within a channel of a metering dial.

The tubular frame 862 can include retention wings or clips 870 locatedat an end opposite of the handle 864. As shown in the illustratedembodiment, the retention wings 870 can be partially cylindricalprotrusions separated by two or more cutouts or slits 871. As such,depending on the material used, the retention wings 870 can be bentoutwardly when receiving a component within the channel 868. In someembodiments, the retention wings 870 can each include a semi-annular lipalong an interior surface of the retention wings 870 which correspondsto an annular slot of a component inserted within the channel 868. Forexample, in some embodiments, the semi-annular lip can correspond to anannular slot 1024 located on a second housing member 1022 (see FIG. 24).As such, the retention wings 870 can allow for a snap fit assembly ofmultiple components of the device thereby facilitating assembly and alsopotentially allowing for disassembly for purposes of reuse and/orresterilization. Other fastening mechanisms and methods can also be usedto connect the components to the plunger body 860 including fastenerssuch as screws, adhesives, welding, and other similar mechanisms andmethods known in the art.

With continued reference to FIG. 16, the tubular frame 862 can include aguard 872 which can extend outwardly from the outer surface of thetubular frame 862. In some embodiments, the guard 872 can run from thebottom end of the tubular frame 862 to a distance toward the top end ofthe tubular frame 862, such as, for example, up to and adjacent thelatch aperture 874. In other embodiments, such as that illustrated inFIG. 16, the guard 872 can be sized so as to not extend to an endsurface of the tubular frame 862 but instead extends only to the cutout871 of the retention wings 870. Similar to other embodiments of theplunger body, such as plunger body 160, the guard 872 can be configuredto fit within slots and rails of the metering dial. In otherembodiments, other forms of metering devices can be used and the guards872 can be configured to correspond to similar structural features onsuch devices.

The guard 872, when positioned between the rails 840, can prevent orsubstantially reduce the likelihood that the plunger body 860 willrotate after activation. This advantageously can prevent or reduce thelikelihood of the plunger body 860 rotating during phases of operationwhich may cause an erroneous concentration of fluid in the injectablevolume. The guard 872 can be sized such that, when the plunger body 860is fully inserted within the channel 834, the guard 872 can be slightlybelow the rails 840 such that the plunger body 860 can rotate freely toselect different concentration values while in a first, “initial,” or“pre-activation” position. However, because the guard 872 is onlyslightly below the rails 840, once extended a short distance, the guard872 can become positioned between the selected rails 840. Thispositioning advantageously allows the guard 872 to lock shortly afteractivation of the apparatus. Furthermore, the guard 872 can extendoutwardly from the tubular frame 860 only a sufficient distance tocontact the rails 840 but not sufficiently outwardly to contact variablestops or similar features located between the rails 840.

With continued reference to FIG. 16, the tubular frame 862 can include alatch aperture 874 configured to allow a latch 928 located on theactivation rod 920 and contained within the channel 868 to protrudeoutwardly from the tubular frame 862. As shown in the illustratedembodiment, the latch aperture 874 can be centered just above thetopmost portion of the guard 872. In other embodiments, the latchaperture 874 can also be located at different positions along thetubular frame 862 and can contain more than one latch aperture ifmultiple latches are used.

As described in greater detail below, in a first, “initial”, or“pre-activation” position, the latch 928 can be sized so as to notextend beyond the guard 872 and thus not contact a variable stop orsimilar structure. When in a second or “open” position, the latch 928can extend outwardly from the tubular frame 862 beyond the guard 872such that the latch 928 can contact the variable stops or similarstructures thereby preventing or significantly reducing the likelihoodof further extension of the plunger body 860 while the latch is in thesecond position. As with other embodiments of the plunger body 860, insome embodiments the latch aperture 874 can be placed such that, if theplunger body 860 is improperly oriented within the metering dial 820during an initial or “pre-activation” phase of operation, the latch 928can be prevented from extending outwardly into the second or “open”position by a rail 840 of the metering dial 820. Furthermore, similar toother embodiments of latch mechanisms, this can also prevent or at leastsubstantially reduce the likelihood that a user will be able to operatethe activation switch 960 thereby preventing or substantially reducingthe likelihood that a user will activate the apparatus when in aninoperable position.

Selector member 866 can be a protrusion extending from the outer surfaceof the tubular frame 862. The selector member 866 can additionallyinclude a selector indicator 876 which can take the form of a minorprotrusion located on the selector ring 866. Selector indicator 876 cancorrespond to the metering indicators 836 located on the metering body822 to indicate the concentration level that will be obtained when theplunger body 860 is oriented in that position when activated.

With continued reference to FIG. 16, the handle 864 can extend in twoopposite directions in a radial direction from the longitudinal axis ofthe tubular frame 862. The handle 864 can be shaped such that a user cangrip the handle 864 and use the handle to either further extend theplunger body 860 rearwardly, for example, to increase the volumecontained in the apparatus or further depress the plunger body 860frontwardly, for example, to reduce the volume contained in theapparatus and eject the injectable volume. The handle 864 canadditionally include a pin aperture 878 for receiving a couplingmechanism, such as a coupling pin, for an activation switch 960. Theactivation switch 960 can thereby rotate about the coupling mechanism inorder to operate an actuation rod 920 which can be located within theplunger body 860.

As will be described in more detail with respect to the operation of aninterlock mechanism shown in FIGS. 18-20, the handle 864 canadditionally include a recess 880 configured to receive the activationswitch 960. The recess 880 can be sized such that, when the activationswitch 960 is in a third or “closed” position, the activation switch 960is fully contained within the recess 880. Furthermore, the handle 864can additionally include an interlock aperture 882 and an interlockchannel 884 configured to receive an interlock member 970 of aninterlock mechanism.

With reference to FIG. 17, an embodiment of an activation system isshown which can include an actuation rod 920 and an activation switch960 which can be used to control the operation of the apparatus. Asshown in the illustrated embodiment, the actuation rod 920 can includean actuator body 922 with a generally cylindrical shape. The actuatorbody 922 can be configured to extend through part of the channel 868 ofthe plunger body 860. In other embodiments, the actuator body 922 can belengthened or shortened depending on the length of other componentscontained within the channel 868. In some embodiments, the actuator body922 can have other cross-sectional shapes such as circles, ovals,ellipses, quadrilaterals, or other polygons. Additionally, the actuatorbody 922 can differ in cross-sectional shape along different portions ofthe actuator body 922. For example, as shown in the illustratedembodiment, the actuator body 922 can have a circular cross-sectionalshape along a first portion of the actuator body 922 and a “+”cross-sectional shape in a second portion. Similar to other embodimentsof the actuation rod, the actuator body 922 can be configured to abutand follow a contoured surface 962 of the activation switch 960 at afirst end of the actuator body 922. In some embodiments, the actuatorbody 922 can be translated within the channel 868 of the plunger body860 when the activation switch 960 is rotated as a result of thecontoured surface 962.

In some embodiments, such as that illustrated in FIG. 17, the actuationrod 920 can include a rod biasing member or mechanism 924 such as ahelical spring or any other similar mechanism. The rod biasing member924 can be configured such that it applies a linearly increasing forceas the rod biasing member 924 is compressed. In other embodiments, therod biasing member 924 can be configured such that it applies anexponentially increasing force as the rod biasing member 924 iscompressed such that the force becomes significantly greater as the rodbiasing member 924 is compressed. As shown in the illustratedembodiment, the rod biasing member 924 can be a helical spring receivedin a recess of the actuator body 922. The rod biasing member 924 can bereleasably fastened to the actuator body 922 such that the rod biasingmember 924 can be removed for purposes of disassembly. In otherembodiments, the rod biasing member 924 can be permanently fastened tothe actuator body 922. In yet other embodiments, the rod biasing member924 can be not connected to the actuator body 922 and can be retainedwithin the recess as a result of being placed between two componentssuch as the actuator body 922 and a first housing member 1020.

As is described in further detail below with respect to the operation ofan embodiment of the activation system shown in FIGS. 25-27, the rodbiasing member 924 can be configured to provide a biasing force againsta housing member 1020. This biasing force can be configured such that itcan exceed a threshold force to activate the release of gas from apressurized chamber within the apparatus. In addition, the rod biasingmember 924 can also be configured to provide a biasing force against theactuator body 922 such that, when the activation switch 960 is movedinto different positions, the actuator body 922 will translate in adirection that will keep the actuator body 922 in contact with at leasta portion of the activation switch 960 such as the contoured portion962.

The actuation rod 920 can include a latch movement portion 926 locatedbetween a first end and second end of the actuator body 922. Similar tothe latch movement portion of other embodiments of the actuation rods,latch movement portion 926 can be used to translate a latch 928 locatedthereon such that the latch 928 can protrude from or retract from anaperture or similar structure located on the plunger (e.g., latchaperture 874 located on the plunger body 860).

With continued reference to FIG. 17, an activator switch 960 can beconfigured to translate the actuator rod 920 through the plunger body860 towards the first housing member 1020 to activate a mechanism forreleasing the gas contained therein. As such, the activator switch 960,like the activator switch of other embodiments, can be a cam with acontoured profile 962 located along the surface configured to contactthe actuator body 922. Activator switch 960 can additionally include anaperture 964 configured to receive a pin (not shown in FIG. 17) suchthat the activator switch 960 can rotate about the pin. It should beappreciated by a person of skill in the art that the activation switch960 can preferably be any type of switch that can remain in a first,second, or more positions without the user needing to maintain theswitch in that position. In the illustrated embodiment, a rotating leveris used. Other switches can also be used such as a screw, latch, springloaded pin, or any other switch known in the art.

With reference to FIG. 18, the activator switch 960 is shown in a first,“initial”, or “pre-activation” position. For example, this can be aposition prior to a first phase of operation. In this first position,the distance between the pin 966 and the contoured surface 962 incontact with the actuator body 922 can be a first distance such that theactuator body 922 is located at a first distance from the end of thetubular frame 862 of the plunger body 860.

As shown in FIG. 19, in some embodiments, the activator switch 960 canbe rotated towards a more vertically oriented position, a second or“open” position, in which the distance from the pin 966 to the contouredsurface 962 in contact with the actuator body 922 can be a seconddistance such that the actuator body 922 is located at a second distancefrom the end of the tubular frame 862 of the plunger body 860. This cancorrespond to the position of the activation switch 960 during a firstand second phase of operation. In some embodiments, the second distancecan be greater than the first distance. As will be described in moredetail with respect to FIGS. 25-27, this can cause the actuator body 922to translate towards the first housing member 1020 of the pressurizedchamber. This translation can activate the release of fluid or gascontained in the pressurized chamber.

As shown in FIG. 20, in some embodiments, the activation switch 960 canalso be rotated towards a more horizontally-oriented position, a thirdor “closed” position, in which the distance from the pin 966 to thecontoured surface 962 in contact with the actuator body 922 can be athird distance such that the actuator body 922 is located at a thirddistance from the end of the tubular frame 862 of the plunger body 860.This can correspond to a third phase of operation and/or a final phaseprior to injection of the injectable volume into a patient. This thirddistance can be less than or equal to the first and/or second distances.In some embodiments, rotation towards the third position can cause theactuator body 922 to translate away from the first housing member 1020of the pressurized chamber such that no fluid or gas is released fromthe pressurized chamber.

With reference back to FIG. 17, an interlock mechanism can be includedto control and limit the movement of the activation switch 960. As shownin the illustrated embodiment, the interlock mechanism can include aninterlock member 970 such as a pawl having interlock wings or clips 972located at one end and an interlock portion 974 (shown in FIGS. 18-20)located at a second end. The interlock clips 972 can be configured to bereceived within interlock apertures 882 or indentations, recesses, orother similar mechanisms to retain the interlock clips 972 located inthe handle 864.

With reference again to FIGS. 18-20, an illustration of the operation ofan embodiment of the interlock mechanism is provided. FIG. 18 is anillustration of the interlock mechanism and activation switch 960 in thefirst, “initial”, or “pre-activation” position. As shown in theillustrated embodiment, the interlock member 970 can be sized and shapedto be received within an interlock channel 884 of the handle 864. Whilein the first position, the interlock clips 972 can be biased inwardly byvirtue of contact between the interlock clips 972 and the inner surfacesof the channel 884.

As shown in the illustrated embodiment, the interlock portion 974 of theinterlock member 970 can be received within a notch or indentation 976located at an end of the activation switch 960. The shape of interlockportion 974 and the notch or indentation 976 can be chosen such that,while in the first or “initial” position, the activator switch 960 canbe prevented or restricted from rotating in a clockwise directiontowards a horizontally-oriented position (i.e., the third or “closed”position) due to resulting interference between the interlock portion974 and the activation switch notch 976. Additionally, the shape of theinterlock portion 974 can be chosen such that, in the first position,the activation switch 960 can rotate in a counter-clockwise directiontowards a more vertically-oriented position (i.e., the second or “open”position). In some embodiments, such as that shown in the illustratedembodiment, the activation switch 960 can include a second contouredsurface 978 configured to translate the interlock member 970 towards anopposite end of the handle 864 when the activation switch 960 is rotatedfrom the first to the second position. In some embodiments, movement ofthe interlock member 970 within the interlock channel 884 towards anopposite end of the handle 864 results in the ends of the interlockclips 972 being translated towards the interlock apertures 882. Uponreaching the interlock apertures 882, the interlock clips 972 which wereoriginally pre-biased inwardly while in the interlock channel 884,expand outwardly such that the interlock clips 972 are received withinthe interlock apertures 882. In some embodiments, the interlock member970 can be prevented from translating back towards the activation switch960 once received within the interlock apertures 882. This canadvantageously prevent or at least substantially reduce the likelihoodthat the interlock member 970 can reengage the activation switch 960 andrestrict movement of the activation switch 960.

FIG. 19 is an illustration of the activation switch 960 and theinterlock mechanism in a second or “open” position. As illustrated, theinterlock clips 972 of the interlock member 970 have been receivedwithin the interlock apertures 882 such that the interlock member 970can no longer translate back towards the activation switch 960. As aresult, a user of the device can rotate the activation switch 960 in aclockwise direction towards the third or “closed” position.

FIG. 20 is an illustration of the activation switch 960 and theinterlock mechanism in the third or “closed” position. In someembodiments, the activation switch 960 can be received within a recess880 in the handle 864 and be flush with a top surface of the handle.Furthermore, the recess 880 can be sized and shaped to closely conformto the shape of the activation switch 960 such that a user of the devicecan have difficulty rotating the activation switch 960 into one of theprior two positions after the activation switch has been fully placed inthe third position.

As such, the interlock mechanism advantageously controls the operationof the activation switch 960 such that a user of the device will notaccidentally rotate the switch 960 in an improper position or in animproper order. Furthermore, because a user of the device may have moredifficulty rotating the activation switch 960 from the third position toone of the prior two positions, there is a reduced likelihood that auser could potentially alter the concentration of the injectable volumeafter the final phase of operation. As such, the interlock mechanismadvantageously serves as a safety mechanism for operation of the device.In other embodiments, other forms of interlock mechanisms may be usedwhich may include the use of other fasteners, clips, or similar devices.A person of ordinary skill in the art would understand that other typesof interlock mechanisms can also be used.

With reference to FIGS. 21-23, an illustration of the operation of anembodiment of the activation system is shown. As shown in theillustrated embodiment, and similar to other embodiments, the latch 928can be contained within the latch aperture 874 such that the latch cannot translate toward a front end or rear end of the plunger body 860. Insuch an embodiment, when the actuator rod 920 translates in a frontwardor rearward direction, the latch 928 is configured to follow the profileof the latch movement portion 926 of the actuator rod 920.

FIG. 21 shows the embodiment in a first, “initial”, or “pre-activation”position. As shown here, the latch 928 can be positioned such that itoutwardly protrudes from the plunger body 860 sufficiently such that, ifextended rearwardly, the latch 928 would contact a variable stop locatedon the metering body 922 and prevent any further extension. In otherembodiments, when in the first position, the latch 928 can be configuredso as to not outwardly protrude from the body 860 to prevent suchextension. When moved to the second or “open” position, as shown in FIG.22, the latch 928 can sufficiently outwardly protrude from the plungerbody 860 such that the latch 928 can contact the variable stop orsimilar structure located on the metering dial 820 thereby preventingany further rearward extension. When rotated to the third or “closed”position, as illustrated in FIG. 23, the latch 928 can be sufficientlyretracted within the latch aperture 874 such that the latch 928 nolonger contacts the variable stop or similar structure located on themetering dial 820 thereby allowing the plunger body 860 to be furtherextended rearwardly.

With continued reference to FIGS. 21-23, a ratcheting member 886 such asa pawl can be attached to the plunger body 860. The ratcheting member886 can be hinged and configured such that the ratcheting member 886 ismovably deformable and provides resistance during deformation. Theratcheting member 886 can correspond to features located on the plungerbody metering dial 820, such as notches 842, to facilitate properorientation with respect to the selected concentration. In order toallow inward deformation of the ratcheting member 886, the actuator body924 can include a recess or indentation 980. This recess 980 can beconfigured such that the ratcheting member 886 is allowed to inwardlydeform only in the first and third positions whereas the ratchetingmember 886 is restricted from deforming inwardly while in the secondposition. This can provide a means of reducing the likelihood that theplunger body 860 can be rotated during operation of the device.

Embodiment of Pressurized Chamber

With reference to FIG. 24, an embodiment of a pressurized chamber isshown along with components of an activation system. As illustrated, thepressurized chamber can have a two-part housing with a first housingmember 1020 and a second housing member 1022 which are translatable withrespect to each other. As shown in the illustrated embodiment, the twomembers 1020, 1022 can have a generally cylindrical shape such that someor all portions of the two members 1020, 1022 can be received within achannel 868 of the plunger body 860. In some embodiments, the twomembers 1020, 1022 can be detached from one another to allow freetranslation of the two members 1020, 1022. In other embodiments, thetwo-part housing can be attached while still allowing translation of themembers 1020, 1022 with respect to each other. Such attachment can beused to increase the stability of the two members 1020, 1022.

As shown in the illustrated embodiment and similar to other embodimentsof the pressurized chamber, an annular slot 1024 can be located on thesecond housing member 1022. In the illustrated embodiment, the annularslot 1024 is located at an end opposite the first housing member 1020however other possible locations can be chosen. The annular slot 1024can be sized and configured to receive the retention wings 870 of theplunger body 860 allowing the second housing member 1022 to be fastenedto the plunger body 860 using a snap-fit connection. To facilitateinsertion of the second housing member 1022 into the channel 868 of theplunger body 860, the inserted end portion can be slightly tapered. Insome embodiments, the second housing member 1022 can be removablyattached to the plunger body 860 thereby allowing replacement of certainparts contained therein. For example, in some embodiments, a storagemember 1030 or canister can be contained within the two-part housing.The two-part housing can also have a plunger end 1060 with a plungerseal 1061 such as a rubber o-ring configured to sealingly contact thesyringe body 1120 and form a seal for defining a chamber to contain aninjectable volume, such chamber potentially serving as a mixing chamber.Other types of sealing members can be used around the plunger end 1060to form such a seal.

FIGS. 25A and 25B are cross-sectional views of the embodiment shown inFIG. 24 when the apparatus is in a first, “initial”, or “pre-activation”position. As illustrated more clearly in FIG. 25B, in the firstposition, the rod biasing member 924, such as a helical spring can be incontact with both the actuator body 922 and the first housing member1020; however, the actuator body 922 may not be in direct contact withthe first housing member 1020. In the first position, the rod biasingmember 924 can exert a force in a frontward direction upon the firsthousing member 1020 and a force in a rearward direction upon theactuator body 922 such that the actuator body 922 remains in contactwith the activation switch 960. In this position, the frontward forceupon the first housing member 1020 can cause the first housing member1020 to apply a force upon a storage member 1030 contained therein asthe first housing member 1020 attempts to translate towards the secondhousing member 1022. Preferably, in the first position, the forceapplied by the first housing member 1020 upon the storage member 1030will be insufficient to translate the storage member 1030 towards thesecond housing member 1022 due to mechanisms contained in the storagemember 1030 (as will be discussed in further detail in FIGS. 28-29). Assuch, while in the first position, any gas or fluid contained within thestorage member 1030 will remain contained within the storage member1030.

FIGS. 26A and 26B are cross-sectional views of the embodiment shown inFIG. 24 when the apparatus is in a second or “open” position. Asillustrated more clearly in FIG. 26B, while in the second position, boththe actuator body 922 and the rod biasing member 924 can be directly incontact with the first housing member 1020. Due to this direct contact,a more significant force can be applied to the first housing member 1020such that the first housing member 1020 can translate in a frontwarddirection thereby causing the storage member 1030 to translate in afrontward direction. This frontward translation of the storage member1030 can then activate the release of gas from the storage member 1030.In other embodiments, the actuator body 922 need not directly contactthe first housing member 1020 since, in such embodiments, the increasein force applied by the rod biasing member 924 due to compression of therod biasing member 924 can be sufficient to cause the first housingmember 1020 to translate in a frontward direction to cause theactivation of the release of gas from the storage member 1030.

FIGS. 27A and 27B are cross-sectional views of the second embodimentshown in FIG. 24 when the apparatus is in a third or “closed” position.As illustrated in FIG. 27B, while in the third position, the actuatorbody 922 may not be in contact with the first housing member 1020.Furthermore, in some embodiments, due to the reduced distance betweenthe pin 966 and the contoured surface 962, the force exerted by the rodbiasing member 924 on the actuator body 922 in a rearward direction cancause the actuator body 922 to translate towards the contoured surface962 such that the actuator body 922 remains in contact with theactivation switch 960. This expansion of the rod biasing member 924results in a reduction of force exerted by the rod biasing member 924upon the first housing member 1020. As a result of this reduced force,and as a result of other mechanisms located within the storage member1030 or canister, the storage member 1030 can be restored to a closedstate thereby preventing any additional gas from being released into thechamber to contain the injectable volume, which can also serve as amixing chamber.

FIG. 28 is a sectional view of an embodiment of a pressurized chamber.The first and second housing members 1020, 1022 have contained therein astorage member 1030 or canister, such as a microcylinder, which containsa fluid such as gas. In some embodiments, the second member 1022 has atan end opposite the first member 1020 a conical or frusto-conicalsurface forming the plunger end 1060. In some embodiments, the secondmember 1022 and the plunger end 1060 form an integral unit. In otherembodiments, the second member 1022 and the plunger end 1060 areseparate units which can be attached using a variety of fasteningdevices and methods such as, but not limited to, fasteners such asscrews and pins, retention clips, adhesives, welding, or the like. Theplunger end 1060 can have an annular slot configured to receive aplunger seal 1061 such as a rubber o-ring to form a chamber for theinjectable volume, which can also serve as a mixing chamber.

The first housing member 1020 can include a recessed portion 1026 orindented portion configured to contact and receive a first end of thestorage member 1030. The shape of the recessed portion 1026 shouldpreferably correspond to the shape of the first end of the storagemember 1030. In other embodiments, the first housing member 1020 may notinclude a recessed portion 1026. The second housing member 1022 caninclude an interior space 1028 sized and configured to receive a secondend of the storage member 1030. In some embodiments, the interior space1028 can include a housing seal 1029 in contact with the second end ofthe storage member 1030. In some embodiments, the housing seal 1029creates a sufficient seal such that little to no gas leaks rearwardthrough the interior space 1028. In some embodiments, the interior space1028 can also provide a generally snug fit around the storage member1030 to ensure that the storage member 1030 generally only translates ina frontward and rearward direction. This advantageously reduces thelikelihood of the seal between the second end of the storage member 1030and the housing seal 1029 from being broken.

With continued reference to FIG. 28, the storage member 1030, such asthe illustrated canister or microcylinder, can include a body portion1040 and a head 1042. As shown in the illustrated embodiment, the bodyportion 1040 can have a generally cylindrical shape with asemi-spherical first end. The body portion 1040, in conjunction with thehead 1042, can form an internal volume 1041 to contain a fluid such as agas in either gaseous or liquid form, or a combination of both, at afirst pressure and concentration which can be different than atmosphericgas. For example, such gases can include, but are not limited to,expansile gases, ophthalmic gases such as SF₆, C₃F₈, C₂F₆, or similargases, propellant gases such as CO₂, refrigerant gases such as N₂0, andother various types of gases. The size of the interior space 1041 can bechosen such that a unit or single-use dose can be contained within thevolume. Other shapes can be chosen for the body portion 1040.

The head 1042 can have a generally tubular shape with an outer diametermatching the inner diameter of the body portion 1040. The head 1042 canhave an internal channel and a flange 1044. As shown in the illustratedembodiment, the first end of the head 1042 can have an opening with adiameter that matches the diameter of the channel and the second end ofthe head can have an opening 1046 with a diameter that is less than thediameter of the channel. In some embodiments, the body portion 1040 andthe head 1042 can be separate components which are later attached. Thispotentially advantageously allows for the assembly of internalcomponents of the head 1042 prior to assembly. Once all components areassembled within the head 1042, the head 1042 can be received within thebody portion 1040 and fastened using devices and mechanisms such asadhesives, welding, or the like. In some embodiments, such as thatillustrated in FIG. 28, the flange 1044 can abut the body portion 1040and adhered or welded along this surface. In other embodiments, the bodyportion 1040 and head 1042 can form an integral unit.

The head 1042 can contain a storage member pressure regulation system,which can form part of a first pressure regulation system, and which cantake the form of an internal valve mechanism within the channel. Theinternal valve mechanism can include a retaining ring 1048, a valve seat1050, an internal biasing member or mechanism 1052 such as a spring, avalve piston 1054, and a piston seal 1056. The retaining ring 1048 canbe placed within an annular slot 1058 located on the head 1042. Theretaining ring 1048 can be made of an elastic material such that theretaining ring can be deformed prior to fitting into slot 1058. Thevalve seat 1050 can be placed between the retaining ring 1048 and thesecond end of the head 1042. In some embodiments, the valve seat 1050can be a ring having an outer diameter approximately equal to theinternal diameter of the head 1042.

The valve piston 1054 can have a generally cylindrical shape and beplaced between the seat 1050 and the second end of the head 1042. Theouter diameter of the valve piston 1054 can be chosen to beapproximately equal to the internal diameter of the head 1042. As shownin the illustrated embodiment, the valve piston can include an annularslot configured to receive the piston seal 1056, fluid pathways 1055 orchannels located along the perimeter of the piston, and a protrusion1057. The fluid pathways 1055 can be configured to allow fluid to passbetween the valve piston 1054 and the head 1042. In the illustratedembodiment, a total of four fluid pathways are included; however, feweror greater numbers of pathways can be used. In some embodiments, theprotrusion 1057 can be a cylindrical member having a smaller diameterthat corresponds to the diameter of the opening 1046. The protrusion1057 can be configured to fit within the opening 1046. In someembodiments, the protrusion 1057 can be flush with the end surface ofthe head 1042. In other embodiments, the protrusion 1057 can be recessedwithin the opening or extend beyond the end surface. A biasing mechanism1052 can be placed between the seat 1050 and the piston 1054 to apply aforce on the valve piston 1054 in a frontward direction such that a sealis formed between the piston seal 1056 and the head 1042. In otherembodiments, other types of valve designs can be used such as a ballvalve, poppet valve, or any other valve mentioned herein or known in theart.

In some embodiments, the internal biasing mechanism 1052 can beconfigured such that, when an activation switch is in a first or“pre-activation” position, the internal valve mechanism will not open asa result of any forces applied to it such as the force applied to thestorage member 1030 via the first housing member 1020 as a result of therod biasing mechanism 924. In some embodiments, the internal biasingmechanism 1052 can be configured such that, when an activation switch isin a second or “open” position, the internal valve mechanism will openas a result of forces applied to it. In some embodiments, the internalbiasing mechanism 1052 can be configured such that, when an activationswitch is in a third or “closed” position, the internal valve mechanismwill not open as a result of any forces applied to it such as the forceapplied to the storage member 1030 via the first housing member 1020 asa result of the rod biasing mechanism 924.

In some embodiments, the storage member 1030 can include otherstructures such as filters integrated in portions of the storage member1030 such as the head 1042. The storage member 1030 can includemembranes or other sealing structures placed over the head 1042 and overthe opening 1046 to provide an additional seal which can advantageouslyextend the shelf life of the storage member 1030. The membrane orsealing structure can be punctured by a protruding member, such as a pin1059, or any other similar release mechanism. In some embodiments, therelease mechanism can be a porous material, for example, known as“frit”. The storage member 1030 can also include additional valvemembers which can serve as a relief valve to reduce the likelihood ofrupturing if the pressure contained within the storage member 1030exceeds certain operational limits. The storage member 1030 can also beconfigured to rupture in a controlled manner to reduce the likelihood ofcatastrophic failure.

In some embodiments, the storage member 1030, and the internalcomponents such as the internal valve, is manufactured from materialsthat are both small and light-weight. The material can also be flexible.In some embodiments, the materials and dimensions of the storage member1030 can be chosen such that the storage member 1030 resists diffusionof gas through the walls of the storage member 1030. This can providethe advantage of increasing storage life of the storage member 1030 whena gas is contained therein. In some embodiments, the length of thestorage member 1030 from a rearward most end of the body 1040 and afrontward most end of the head 1042 can range from approximately 15 mmto approximately 65 mm, from approximately 20 mm to approximately 45 mm,and from approximately 25 mm to approximately 35 mm, such as 29 mm. Insome embodiments, the outer diameter of the body 1040 can range fromapproximately 4 mm to approximately 25 mm, from approximately 6 mm toapproximately 20 mm, and from approximately 8 mm to approximately 15 mm,such as 9.5 mm. In some embodiments, the outer diameter of the head1042, not including a flange portion can range from approximately 2 mmto approximately 20 mm, from approximately 4 mm to approximately 15 mm,and from approximately 6 mm to approximately 10 mm, such as 7.5 mm.

With continued reference to FIG. 28, the second housing member 1022 caninclude a release mechanism 1059 located within a channel 1062. Therelease mechanism 1059 can be substantially centered over the protrusion1057 of the valve piston 1054 and have a diameter which matches thediameter of the opening 1046. As illustrated in FIG. 29, duringoperation, when the storage member 1030 is translated in a frontwarddirection towards the release mechanism 1059, the release mechanism 1059remains stationary such that the release mechanism 1059 can cause thevalve piston 1056 to unseat from the head 1042 thereby allowing the flowof fluid from the storage member 1030, past the pathways 1055 and therelease mechanism 1059, and through the channel 1062 where it ultimatelycan flow into a chamber for the injectable volume, such as a mixingchamber. In some embodiments, the release mechanism 1059 can be made outof a porous material such that the release mechanism 1059 itself servesas a preliminary filtering mechanism for fluid flowing through channel1062. In some embodiments, filters can be added between the releasemechanism 1059 and the end of the channel 1062 or at any other locationto filter out materials.

With reference to FIG. 30, an embodiment of a chamber for an injectablevolume, such as a mixing chamber, is shown which can include a syringebody 1120, a syringe pressure regulation system, which can form part ofa second pressure regulation system, and various components of theabove-mentioned systems. Syringe body 1120 can have a cylindrical bodyand a nose 1122 at a front end. In some embodiments, a threaded nozzle1124, which can include multiple components of a pressure regulationsystem, can be removably attached to the nose 1122 of the syringe body1120. This can advantageously facilitate assembly of the apparatus byallowing the pressure regulation system to be assembled within thesmaller nozzle 1124 prior to being incorporated with the syringe body1120. The nozzle 1124 can be attached to the nose 1122 using multiplefastening devices and means such as screws, adhesives, snap fits,welding, or the like. The chamber for an injectable volume can bedefined by the inner walls of the syringe body 1120 and the plunger seal1061. Furthermore, as with other embodiments of the syringe, the syringebody 1120 can also include indicators along its outer surfacecorresponding to a chosen concentration and a flange at a rear end ofthe body 1120 configured to be attached to a metering dial.

With continued reference to FIG. 30, an embodiment of the syringepressure regulation system is shown comprising a valve body 1220, avalve end 1222, a valve piston 1224, a piston seal 1226, a pistonbiasing member or mechanism 1228, a valve biasing member or mechanism1230, and a valve end seal 1232. Similar to other embodiments of thepressure regulation system, the valve body 1220 and valve end 1222 canslidingly translate within the threaded nozzle 1124.

In a first position, such as that illustrated in FIG. 30, the valve end1222 can rest against a lip 1234 of the threaded nozzle 1124 due toforce exerted by the valve biasing member 1230 on the valve body 1220and valve end 1222 in a frontward direction. In the first position, thevalve piston 1224 and valve seal 1226 can form a seal and limit, orprevent, the passage of fluid through the valve body 1220. However, whenthe pressure in the chamber for an injectable volume increases beyond athreshold value to overcome the biasing force exerted by the pistonbiasing member 1228, the valve piston 1224 can be translated in afrontward direction against the force applied by the piston biasingmember 1228 and fluid can pass through the valve body 1220 and valve end1222 and into the atmosphere. Once the pressure reduces back to athreshold value, the equilibrium of forces allows the valve piston 1224and valve seal 1226 to once again sealingly contact the valve body 1220.

In a second position, the valve body 1220 and valve end 1222 can betranslated in a rearward direction against the valve biasing member1230. For example, this can be accomplished by applying a force in therearward direction upon the valve end 1222. In the second position,contact between the valve piston 1224 and an internal protruding member1126 of the syringe body 1120 can cause the valve piston 1224 to move ina rearward direction relative to the valve body 1220 and valve end 1222such that the valve piston 1224 no longer sealingly contacts the valvebody 1220. This could, in some embodiments, allow the passage of fluidto and from the chamber for an injectable volume. In some embodiments,the pressure regulation system can be forced into a second position whenan inline filter is threaded onto the threaded nozzle 1124. For example,an attachment 760 as illustrated in FIG. 14. Other types of attachments,such as stopcocks, valves, tubing, or the like, can also be attached tothe threaded nozzle 1124.

External Gas Filling

In some embodiments, the pressurized chamber can be external to theapparatus. In such embodiments, the pressurized chamber can be a tank orother canister containing the gas in liquid or gaseous (or acombination) form. In some embodiments, the tank can be attached to thethreaded nozzle via tubing or other mechanisms. The connection betweenthe threaded nozzle and tubing can cause the pressure regulation systemlocated on the apparatus to be forced open thereby allowing the gas fromthe tank to be input into the chamber. In some embodiments, introductionof the gas from the tank can be performed during a first phase ofoperation. As such, the gas from the tank can fill the apparatus withgas until the apparatus reaches a configured first volume. In someembodiments, the tank can have a regulator such that the apparatus isfilled with gas at a regulated pressure. The connection can then beremoved from the threaded nozzle, allowing the valve to functionnormally. In some embodiments, since the gas can be at a higher pressurethan atmospheric air and can exceed a threshold value for the pressureregulation system, the gas can be expelled or bled from the system untila configured pressure is achieved in the apparatus. Once the configuredpressure is achieved in the apparatus, the remaining phases of operationcan then be completed in a similar manner to those in theabove-described embodiments.

The foregoing description is that of an apparatus and method for mixingand/or injecting gases having certain features, aspects, and advantagesin accordance with the present inventions. Various changes andmodifications also can be made to the above-described gas mixtureapparatus and method without departing from the spirit and scope of theinventions. Thus, for example, those skilled in the art will recognizethat the invention can be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other objects or advantages as canbe taught or suggested herein. In addition, while a number of variationsof the invention have been shown and described in detail, othermodifications and methods of use, which are within the scope of thisinvention, will be readily apparent to those of skill in the art basedupon this disclosure. It is contemplated that various combinations orsubcombinations of the specific features and aspects of the embodimentscan be made and still fall within the scope of the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the disclosed gas mixtureapparatus.

What is claimed is:
 1. A hand-held gaseous injector apparatus,comprising: a syringe body with an outlet; a plunger slidably disposedin the syringe body and with the syringe body, defining a first chamberwithin the syringe body; a metering device, at least partially withinthe syringe body, configured to control a volume of at least the firstchamber when a first fluid is introduced into the first chamber, whereinthe metering device comprises a plurality of protrusions disposedinwardly from an inner wall of the metering device and a moveableselector with a protrusion that can be moved between positions inalignment with the plurality of protrusions disposed inwardly from theinner wall of the metering device, wherein each of the plurality ofprotrusions comprises a surface configured to contact the protrusion ofthe moveable selector to limit movement of the plunger to one of aplurality of different positions, each different position correspondingto a different volume of the first chamber; and a filling mechanismconfigured to direct the first fluid into the first chamber of thesyringe body so as to move the plunger and expand the first chamber. 2.The hand-held gaseous injector apparatus of claim 1, further comprisinga second chamber, the second chamber comprising an internal volumecontaining at least a first gas in a concentration different than thatin atmospheric air and at a pressure greater than that of thesurrounding atmospheric air.
 3. The hand-held gaseous injector apparatusof claim 2, wherein the second chamber is external to the hand-heldgaseous injector apparatus.
 4. The hand-held gaseous injector apparatusof claim 2, wherein the second chamber is a storage member, the storagemember comprising an opening at a first end and an internal valvemechanism located adjacent the first end, the internal valve mechanismconfigured to seal the opening.
 5. The hand-held gaseous injectorapparatus of claim 4, wherein the internal valve mechanism comprises apiston, a seal, and a biasing member, the internal valve mechanismconfigured to seal the opening at least prior to activation of thesystem.
 6. The hand-held gaseous injector apparatus of claim 5, whereinthe internal valve mechanism does not seal the opening during phases ofoperation when an activation system is in an “open” position.
 7. Thehand-held gaseous injector apparatus of claim 4, wherein the storagemember comprises a membrane over the first end so as to seal theopening.
 8. The hand-held gaseous injector apparatus of claim 4, whereinthe storage member comprises a relief valve configured to release thefirst gas when pressure within the storage member exceeds apreconfigured value.
 9. The hand-held gaseous injector apparatus ofclaim 1, further comprising a release mechanism, wherein the releasemechanism comprises a pin.
 10. The hand-held gaseous injector apparatusof claim 9, wherein the release mechanism comprises a porous material,the porous material configured to at least partially filter the firstgas.
 11. The hand-held gaseous injector apparatus of claim 1, furthercomprising an activation system configured to commence and controloperation of the apparatus.
 12. The hand-held gaseous injector apparatusof claim 11, the activation system comprising an activation switch andan interlock mechanism configured to restrict movement of the activationswitch such that the activation switch is hindered from moving in animproper order.
 13. The hand-held gaseous injector apparatus of claim12, wherein the interlock mechanism, when the activation switch is in afirst position, hinders movement towards a third position.
 14. Thehand-held gaseous injector apparatus of claim 12, wherein the interlockmechanism, when the activation switch is moved from a first position toa second position, does not hinder movement towards a third position.15. The hand-held gaseous injector apparatus of claim 12, wherein theactivation switch, when in a third position, is received within a recessof a handle of the plunger.
 16. The hand-held gaseous injector apparatusof claim 15, wherein the activation switch is flush or placed entirelywithin the recess of the handle.
 17. The hand-held gaseous injectorapparatus of claim 1, further comprising an activation system.
 18. Thehand-held gaseous injector apparatus of claim 17, wherein the activationsystem comprises an activation switch, an actuator body, and a biasingmember, the biasing member configured to exert a force on at least oneof an actuator body and a housing member.
 19. The hand-held gaseousinjector apparatus of claim 4, further comprising a housing configuredto receive the storage member.
 20. The hand-held gaseous injectorapparatus of claim 19, the housing comprising two portions, wherein thetwo portions are configured to translate towards each other to activatethe release of gas from the storage member.
 21. The hand-held gaseousinjector apparatus of claim 1, wherein the protrusion of the moveableselector comprises a latch.
 22. A hand-held gaseous injector apparatus,comprising: a syringe body with an outlet; a plunger slidably disposedin the syringe body and with the syringe body, defining a first chamberwithin the syringe body; a metering device at least partially within thesyringe body, the metering device being configured to limit the volumeof at least the first chamber when a first fluid is introduced into thefirst chamber, wherein the metering device comprises a latch that can bemoved between a plurality of positions in which the latch is alignedwith a plurality of different protrusions, respectively, wherein theplurality of different protrusions are disposed inwardly from an innerwall of the metering device, wherein each of the plurality of differentprotrusions comprises a surface configured to define a point of contactwith the latch to limit movement of the plunger to one of a plurality ofdifferent discrete positions, each discrete position corresponding to adifferent limit of the volume of the first chamber.
 23. The hand-heldgaseous injector apparatus according to claim 22, wherein the outlet ofthe syringe body comprises a nozzle and a valve disposed in the nozzle.